|The little girl they were all waiting for was 8-year-old Jenessa Byers - also known as Boey.
She captured the show producers' hearts with her crusade against cancer on YouTube.
"It's hard to not be inspired by a little girl who has fought cancer - well, now for the second time," said Ed Sanders, an Extreme Makeover designer. "And all the while fighting it, she's going in the hospital trying to put a smile on other kids who are suffering from cancer. For me, this is why we do this show."
Boey is suffering a recurrence of a rare form of cancer that has a 70-percent survival rate. The illness left her family financially drained and unable to fix their home, which was filled with toxic mold and an unstable foundation.
Health experts had told the family their home was too dangerous for Boey and her brother, who is autistic.
On Monday, round-the-clock construction began on the family's new 4,000-square-foot, four-bedroom house.
"We've had probably 1,500 to 2,000 workers on the house this week," said Vern Malen of Legend Homes.
No news cameras were allowed inside Saturday, but one of the show's designers gave KATU News a hint of what is inside.
"When we've got a young family that knows exactly what they want - they love the Asian theme, they love zen, they like calming influences - once they tell us what they like, we can really, really run with it," said Sanders, one of the designers. "And we just went with it big time."
ABC flew the family to South Carolina while their new home was being built this week. They arrived Saturday evening to much fanfare. When Jenessa first glimpsed her new home she cried tears of joy.
The episode is expected to air on the hit TV show in late September or early October